Clock and watch



Jan. 6, 1942. v. VIRTANEN CLOCK AND WATCH Filed Dec.. 7, 1940 INVENTOR Q26 Valdemar li'rianm BY 57mm kvw TM,-

ATTORNEYS Patented Jan. 6, 1942 UNITED STATES PATENT OFFICE CLOCK ANDWATCH Valdemar Virtanen, Morristown, N. J. Application December 7, 1940,Serial No. 368,998

4 Claims.

This invention relates generally to clocks and watches, and hasparticular reference to improvements in instruments of that generalcharacter which have escapement mechanisms controlling and regulatingthe release of a motive force applied by weights or springs to a geartrain for moving the hands or corresponding parts of a time indicator.

The main object of the invention is to increase the time keepingaccuracy of clocks and watches of the class mentioned. The escapementmechanism of such time pieces has been the subject matter or study anddesign for hundreds of years and a number of changes in the shapes andrelations of parts have been made with a view to increasing the accuracyof movement and consequent accuracy of the time indication. Neverthelessvariations fromaccurate time keeping still exist generally and are duein large part to uncontrolled and undesirable movements in the parts ofthe escapement arising mainly because of improper release of the escapewheel by the pallet. Applicanthas reduced such irregularities to aminimum by steadying the pallet in its movement, thereby giving bettercontrol over the escape wheel and, as the escape wheel regulates therelease and transmission of power, the time keeping accuracy iscorrespondingly improved. By steadying the pallet as contemplated by theinvention, a well constructed and adjusted watch which had a. variationof five seconds in twenty-four hours showed a variation of only onesecond, while clocks and watches which, because of their lack ofprecision in workmanship and adjustment, had much greater variationsfrom accurate operation were improved by the invention to such an extentas to make them keep time as well or betterthan correspondinginstruments where the quality of workmanship and adjustment was muchgreater and the cost correspondingly higher.

The invention may be embodied in clock and watch movements now in use oras at present manufactured without radical changes in existing designs.That is to say, the invention can be applied in repairing and adjustingclocks and watches which are now in use and manufacturers will not haveto re-design or alter the construction of their product to any importantextent in embodying the invention.

The invention consists in a novel combination and relation of parts in aclock or watch movement, embodiments of which are hereinafter describedwith reference to the drawing accompanying and forming a part of thisapplication,

the novel features being pointed out in the claims appended hereto.

In said drawing:

Fig. 1 is a plan view of a well-known watch escapement with theinvention applied thereto. The parts are greatly enlarged in Fig. 1 andare shown as they would appear in looking down on Fig. 2.

Fig. 2 shows the same parts as Fig. 1 and is a view of those parts asthey would appear if looking upward from the bottom of Fig. 1.

Fig. 3 illustrates a pallet arbor which has been reduced incross-section according to the invention.

Fig. 4 is a side elevation of the pallet arbor which is shown partly insection in Fig. 3.

Figs. 5 and 6 show, respectively, modifications of the invention.

The constructions shown in the drawing are illustrative only because, aswill be more clearly apparent later on, the invention can be applied toany clock or watch which has an escapement pallet or equivalent part.Referring to Fig. 1, the escape wheel I0 is, as before stated, part of awell-known escapement mechanism and is carried by an arbor I I supportedat its ends for free rotation in jewels or other bearings in the framesor other stationary supports for the mechanism. Cooperating with theteeth of the escape wheel I0 is an escapement pallet I2 attached to anarbor I3 pivoted at its ends in a framework or supports for themechanism. In the particular movement shown, pallet stones I4 and I5 ofa durable antifriction material cooperate directly with the teeth of theescape wheel. At its other end of the part has a fork slot cooperatingwith a jewel pin I6 of the roller part of the escapement and themovements of the pallet are limited in a wellknown manner by bankingelements I! and I8. In the particular escapement illustrated, the palletarbor I3 has an oscillating movement which is small in angular extent,being sufficient only to intercept one tooth on the escape wheel asanother is released. As the flat end of an escapement tooth passes thepallet stone I4, the pallet is given an impulse which is in thedirection of the pallet arbor. In all clocks and watches having anescapement, the escapement wheel and the pallet cooperate to give a,corresponding impulse to the pallet. This mechanism, no matter how welldesigned, causes variations in the movement of the escape wheel which,while in themselves of no great magnitude, are cumulative in theireffect upon the train of the movement. In order to minimize theirregularities mentioned,

the invention contemplates steadying the oscillations of the pallet andits arbor. This is accomplished by having a spring in light frictionalengagement with the arbor of the pallet, the spring thereby acting as adamper or steadying device for the pallet arbor movements. The spring2!, shown in Figs. 1 and 2, is a fiat spring which may be no heavierthan the hair spring of the particular movement, although the tension onthe spring is more important than the cross sectional area of thespring. One end of the spring is secured to a bracket 22 which issecured to any convenient stationary part 23 of the movement. Thissupport for the spring will vary according to the construction of themovement or rather the location of the frame or support to which thespring is attached.

The arbor I3 shown in Figs. 1 and 2 is enlarged or has sleeves holdingthe pallet in place, and if the spring were simply to engage theexterior of the enlarged part, the angular movement of the arbor wouldgive'a leverage against the spring which might, to some extent, ofisetthe advantages of the invention. In such cases it is preferred to reducethe diameter of one of the sleeves or the enlarged part of the palletarbor so as to provide what is for convenience referred to as a knifeedge 24 parallel to and, preferably, close to the axis of rotation ofthe pallet arbor. The height of the knife edge should be a littlegreater than the radius of the arbor, that is, the axis of the arborshould pass through the knife edge somewhere near the apex or angle ofthe knife edge. The exact height of the knife edge is not importantsolong as the leverage against the spring is reduced to the degreenecessary. The free end of the spring 2! may rest directly upon the apexor angle of the knife edge as the angular movement of the edge is ofsmall magnitude, but it is preferred to secure to the free end of thespring 2| a piece ofanti-friction material 25 for contact with the knifeedge. Any suitable material may be used, although the material used forthe pallet stones i4 and i5 is suitable for the purpose. The mounting ofthe spring 2| on its stationary support is such as to hold the springunder tension and apply that tension to the pallet arbor. This serves tocushion the movements of the pallet and steady the pallet arbor in itsbearings so that uncontrolled and disadvantageous movements of thepallet and escape wheel are greatly reduced. In constructions where thepallet arbor is simply a spindle the free end of the spring may restdirectly against the periphery of the spindle 25 as shown in Fig. 6 orthe spring may carry a piece of anti-friction material 25 in contactwith the spindle as shown in Fig. 5.

In describing the construction illustrated in Figs. 1 to 4 inclusive,the term knife edge has been used but it is, of course, obvious thatinstead of a sharply defined edge a rounded surface generated on a shortradius from the axis of the arbor may readily be employed. In fact, theconstructions illustrated in the drawing are more or less diagrammaticfor the purpose of illustration and explanation of the invention. Forexample, one simple modification might be the use of a round Wire springof suitable tension in place of the flat spring Zia illustrated in Fig.5 or 251) illustrated in Fig. 6. The particular form and construction ofthe spring is not essential, it being necessary merely for the spring toapply a reliable and uniform light damping pressure to the pallet arbor.

The invention is capable of various other changes in the construction,shape and relation of parts according to the environment in which it isplaced, and it is not the desire to be limited to any specificconstruction, except to the extent indicated in the claims which follow.

What is claimed is:

1. A Watch or clock movement comprising an escape wheel, a pallet andallet arbor, said arbor having-a portion of reduced diameter forcooperation with a spring for steadying the movements of the arbor andpallet, a spring for the purpose stated, and mounting means for the 7spring constructed in such manner as to hold the spring at a right angleto the length of the arbor and under constant tension against thereduced portion of the arbor.

2. A watch or clock movement comprising an escape wheel, a pallet andpallet arbor, said arbor having a portion of reduced diameter forcooperation with a spring for steadying the operating movements of thearbor, a spring for the purpose statedhaving an anti-friction surface engaging said portion of reduced diameter, and mounting means for thespring constructed in such manner as to hold the spring under constanttension with said anti-friction surface engaged against the reducedportion of the arbor.

3. A clock or watch movement having an escape wheel, a palletcooperating with the escape wheel and a pallet arbor, said arbor havinga portion of its length constructed to provide a knife edge parallel tothe longitudinal axis of the arbor, a spring engaging the knife edge,and means for holding the spring under tension against the knife edge.

LA clock or watch movement having an escape Wheel and a palletcooperating with the escape wheel, an arbor for the pallet, said arborhaving a portion of its length constructed to provide a knifeedgeparallel to the longitudinal axis of the arbor, a spring carrying ananti-friction member and supporting means for the spring constructed tohold the spring under tension with the anti-friction member inengagement with the knife'edge.

VALDEMAR VIRTANEN.

